The trial was presided over by U.S. District Court Judge Earl R. Larson between June 1, 1971, and March 13, 1972, in Minneapolis, Minnesota, a jurisdiction decided when D.C.
Attorneys for Sperry Rand wanted the case to be tried in Washington, D.C., a district perceived to be friendlier to the rights of patent holders; by contrast, Honeywell was at the time the largest private employer in Minnesota.
A computerized record of documents pertaining to the case, known as Electronic Legal Files (or ELF), allowed Honeywell attorneys to store, sort, recall, and print information on hundreds of different subjects.
More than seven months following the end of courtroom testimony, Judge Earl R. Larson's decision was published on October 19, 1973, in a document, over 248 pages long, titled Findings of Fact, Conclusions of Law, and Order for Judgment.
(In the discovery process leading up to Honeywell v. Sperry Rand, this device came to be called the Atanasoff–Berry Computer, or ABC; Clifford Berry had been Atanasoff's graduate student assistant in the computer development project in the basement of the physics building at Iowa State College and in 1942 the two of them left Iowa State for positions in war research—Atanasoff in Washington, D.C., and Berry in Pasadena, California.)
Considered to be particularly damning to the Sperry Rand case were the following often-quoted excerpts: A number of different ideas have come to me recently anent computing circuits—some of which are more or less hybrids, combining your methods with other things, and some of which are nothing like your machine.
Honeywell v. Sperry Rand and the decision it culminated in emphasized the differences between the ENIAC and the ABC, some of which were: Following the ruling, some writers perceived recognition of Atanasoff for his title as "father of the computer" was slow in coming, and wrote books of their own.